Kelly rod and drive bushing therefor



Jan. 4, 1944. w. T. CALDWELL KELLY ROD AND DRIVE BUSHING THEREFOR ATTORNEY 25h t sh t1 Patented Jan. 4,

KELLY non AND DRIVE RUSHING TnEREFoR.

- walter 'i'. Caldwell, Enid, ok1a.,assignor to 'rile George E. `FailingSupply Company, Enid, Okla.,- a corporation of Oklahoma lApplicationJune 28', 19471,` Serial No. 409,322

(Cl. Z55-'23) 12 Claims.

This invention relates to rotary drilling apparatus, and moreparticularly to a Kelly v'rod and drive bushing therefor, theapplication for patent for the present invention .being a continuationin part of avcopendin-g applicationl for patent on ."Kelly rodand drivebushing therefor filed January20, 1939, Serial No: 251,966, nowabandoned. Y When a'- drill feeding mechanism is used in conjunctionwith a drill rotating mechanism it is diiiicult to grip a conventionalKelly rod with the feed chuck of the'feeding mechanism due to thecross-sectional shape thereof, and any deformity in the Kelly rodproduced by the gripping chuck interferes with movement of the Kelly rodthrough the drive bushing. Consequently the Kelly rods are constructedto provide considerable looseness between the rods and bushings. 'I'hisloosenessproduces considerable back-lash and wear due to batteringcaused by resistance of bit rotation under power of the rotary.

vI therefore provide a Kelly rod of circular crosssection which can begripped by the chuck and slide freely through a circular bore in thedrive bushing of the rotary mechanism and provide the bushing withrelatively close fitting drive keys operable in longitudinal grooves ofthe Kelly rod.

I am A aware that it has been suggested to drive Kelly rods with keys,but such keys have not proved satisfactory because the keys tend to bindthe kelly within the drive bushing and prevent free sliding movement ofthe Kelly rod through the bushing.

It is an object of the invention to overcome this diiiiculty byproviding cylindrical rod-like keys which are positioned in grooves ofthe kelly and bushing in such amanner that driving contact area betweenthe bushing and keys is substantially equal to the driving contactbetween the keys and Kelly rod with the resultant forces of the drivingconnection acting diametrically through the axes of the keys.

Another diihculty in rotary `drilling mechanisms is that the Kelly rodmoves through the drive bushing as the drilling progresses and entersthe bore-hole below the drilling table so that it is coated withdrilling fluid and mud when itis retracted through the table to addanother section of drill pipe. Since there is clearance space betweenthe drive bushing and Kelly rod, the

drilling fluid and mud are barried into the bore of the drive bushing,and being of abrasive character are apt to cause rapidwear of the kelly,drive bushing, and the rod-like or cylindrical keys. A lack of adequatelubrication aggravates the wearing action.

Therefore, rfurther objects ofthe present invention are to provide theKelly rod bushing with means for wiping the drilling fluid from theKelly rod when the Kelly rod is moved therethrough; and to provide forpressure lubrication of the driving faces to resist wear and entrance ofthe drilling fluid into .the bushing.

In accomplishing these and other objectsof the invention, as hereinafterpointed out, I have provided improved detailsof structure, the preferredforms of which are illustrated in the accompanying drawings, wherein: y

Fig, 1 is a vertical section through a drill rotating mechanism equippedwith a kelly and drive bushing embodying the features of the presentinvention.

Fig. 2 is a horizontalfsection through the drive bushing and kelly onthe line 2-2 of Fig. 1.

Fig. 3 is a perspective sectional view of the Kelly drive bushingremoved from its seat in the turntable of the rotary mechanism.

Fig. 4 is an enlarged horizontal section on the line 4-4 of Fig. 1,particularly illustrating the keying elements and the clearance spacebetween the bushing and Kelly rod.

Fig. 5 is a diagrammatic View showing the drive contact areas betweenthe Kelly rod, drive bushing and rod-like keys whereby the thrustsacting on the keys are substantially equal.

Fig. 6 is a section through a drill rotating mechanism for actuating aconventional Kelly rod of polygonal cross-section, and equipped with amodified form of drive bushing to accommodate the conventional Kellyrod.

Fig. 7 is a horizontal section through the drive bushing and kelly onthe line 1-1 of Fig. 5.

Fig. 8 is a perspective sectional view of the modified form of drivebushing.

Fig. 9 is a horizontal section through the drive bushing and kelly onthe line 9 9 of Fig. 8.

Referring more in detail to the drawings:

i designatesa rotary mechanism such as used in connection withconventional. drilling rigs for rotating the drilling string. The rotarymechanism includes a. turntable 2 that is mounted on, a gear `housing 3,which is adapted to be secured to the platform of the drilling rig (notshown). The rotary table 2 is preferably mounted on antifrictionbearings 4 and carries a ring gear 5 meshing with a pinion gear 6. Thepinion gear 6 is fixed on a drive shaft 1 that is connected with a primemover (not shown), usually forming a part of the drilling rig. Theturntable 2 has a central opening 3 forming a conical seat 9 for a drivebushing I slidably keyed relatively to a Kelly rod II which extendstherethrough. The drive bushing includes a substantially conicalshapedbody I2 having a tapered exterior I3 engaging the seat 9, whereby thebushing is wedged within the turntable to rotate therewith. The drivebushing also includes laterally extending lugs I4 that engage in socketsI5 formed in the turntable to provide a positive driven connectiontherewith. The Kelly rod Il is of circular crosssection and smaller indiameter than the bore I3 of the drive bushing to provide clearancespace I3' therebetween whereby the Kelly rod is freely slidably throughthe drive bushing while the parts are under load incidental to rotationof the bushing and resistance'oflered by the drill bit.

The Kelly rod illustrated in Figs. 1 and 2 is formed of tubular stock toprovide a channel I1 through which a drilling fluid is delivered to thedrill pipe by way of a swivel head (not shown), which is attached to theupper end of the Kelly rod. 'I'he circular periphery of the Kelly rod isprovided with a plurality of longitudinal grooves or flutes I8 ofsemicircular crosssection and shown as three in number, to engagedriving keys I9 seated in registering semicircular grooves 20 formed in,the face of the bore I6. 'I'he drive members or keys are of cylinder orrod-like shape having substantially close but sliding fit within thesubstantially semicircular grooves,` The keys have less length than thebushing to accommodate sealing elements 2l and 22, later described, Dueto the clearance space I6', and the relatively close fit of the keys,the grooves are slightly less than semicircular but they are ofsubstantially equal depth in both the Kelly rod and bushing so that thedriving contacts of the keys with the bushing and with the Kelly rod aresubstantially equal, as shown in Fig. 5. The axial centers of the keystherefore are in the space I3' and the driving connection between thebushing and the Kelly rod is through the diameter of the keys toequalize the pressure thereof against the walls of the respectivegrooves so they will not interfere with free sliding movement of theKelly rod when under driving load. The keys have relatively close fltwithin the grooves so as to prevent radial play between the Kelly rodand drive bushing, thereby avoiding wear incidental to looseness. Theshape of the keys permits free sliding movement of the Kelly rodthroughthe bushing while they are retained therein from axial movement by meansof the sealing elements now to be described. 'I'he driving pressuresbeing equal, the keys maintain the Kelly rod concentric with the bore ofthe drive bushing.

Formedin the upper and lower ends of the drive bushing are counterbores23 and 24, forming shoulders 25 and 25 substantially in registry withthe ends of the keys as clearly shown in Fig. 1. Inserted within thecounterbores, and engaging the shoulders, are rings 21 and 23 to engagethe ends of the keys. Also inserted in the bores are packing rings 29and 30, which are engaged by packing glands or followers 3| and 32. Therings 21 and 28 preferably have tongues 33 projecting from their innerperiphery to closely engage in the grooves I8 of the Kelly rod tosupport similarly shaped tongues 34 of the packing rings, which alsoenter and seal the grooves of the kelly. The packing followers includecollars 35 of suitable diameter to pass over the kelly and into thecounterbores, The collars It is thus obvious that when the screws 33 aretightened, the followers 3l and 32 are moved Ainto compressing relationwith the packing rings 29 and 30, and the packing rings are forced intosealing contact with the circumferential face of the Kelly rod so as toeffect a seal therebetween.

The packing rings also form wipers for removing drilling fluid from vtheface and grooves of the rod before they pass into the bushing, so thatthe portions of the Kelly rod engaged by the inner bore of the bushingand the driving keys are free of drilling fluid. Since the drillingfluid is excluded from the bushing, it is, therefore, possible tolubricate the keys and bore of the bushing so as to further reduce wearand promote smoother driving action between the bushing and Kelly rod.

In order to supply the lubricant, the bushing III is provided with achannel 43 which extends downwardly from the upper end of the bushingand terminates substantially in the center thereof, as shown in Fig. 1.The outer end of the channel is counterbored and threaded, as at 44, toaccommodate a pressure fitting 45 having a check valve 43 therein forclosing the channel. It is thus obvious that by applying a pressuregrease gun to the fitting, the lubricant or grease may be forced intothe interior of the bushing and retained by the packings underpressure.Therefore the clearance space I6' between the kelly and drive bushing,as well as those surrounding the driving keys, is filled with lubricantunder sufficient pressure to exclude further the possibility of drillingfluid entering the driving portion of the bushing. If desired, thewashers 21 and 23 may be retained against the shoulders 25 and 23 bymeans of spring rings 41 engaged within grooves 43 in the walls of thebores and having portions projecting over the washers.

The drive bushing 49, illustrated in Figs. 6

to 9 inclusive, is substantially the same construction as that shown inFigs. 1, 2 and 3, with the exception that it is provided with apolygonal bore 50 and is equipped with similar packing elements 43, 5Iand 52 at the respective ends thereof. The packing rings, however,conform in shape to the cross-sectional shape of the Kelly rod 53, theillustrated instance being a Kelly rod of hexagonal section. However, itis obvious .that a similar bushing may be provided for any conventionalshaped Kelly rod vsi'ithout departing from the spirit of the invent on.

From the foregoing it is obvious that I have provided a Kelly rod anddrive bushing assembly constructed to provide free sliding movement ofthe Kelly rod in the bushing, and have provided means to exclude thedrilling fluid from the driving connection. I have also provided thebushing with a lubricant supply so that closer tolerances may beeffected between the driving faces of the bushing and Kelly rod.

What I claim and desire to secure by Letters Patent is:

l. In a drill rotating mechanism, a Kelly rod of circular cross-sectionand having longitudinal grooves of substantially semicircularcross-section, a driving bushing having a cylindrical bore of slightlylarger diameter than the diameter of the Kelly rod to provide aclearance space therebetween iorfree sliding movement `of the Kelly rodvthrough the bushing, said bushing having groovesv of substantiallyvsemioircular cross-section registering with the grooves-in the Kellyrod and cooperating therewith to provide recesses of circularcross-section, cylindrical keys closely fitting within said. recessesvand having driven contact with 'the `bushing substantially equal inarea tov driving contact with theKelly rod, and means at the ends of thebushing engagingly retaining said cylindrical keys to preventlongitudinal movement of the keys in the bushing.r i

2. In a` drill rotating mechanism, a Kelly rod of circular cross-sectionand having longitudinal grooves of substantially semioircularcross-section, a driving bushing having a cylindrical bore of slightlylarger diameter than the diameter oi.' the Kelly rod to provide aclearance space therebetween for free sliding movement of the Kelly rodthrough the bushing, said bushing having grooves of substantiallysemicircular cross-section registering with the grooves in the Kellylrod and cooperating therewith to provide recesses of circularcross-section, cylindrical keys closely fitting within said recesses andhaving driven contact with the.bushing substantially equal in area todriving contact with the Kelly rod, said driving and driven contactareas being located on diametrically opposite sides oi said keys, andmeans at the ends of the bushing engagingly retaining said cylindricalkeys to prevent longitudinal movement of the keys in the bushing.

3. In a drill rotating mechanism, a Kelly rod,l of circularcross-section and having longitudinal grooves of substantiallysemioircular cross-section, a driving bushing having a cylindrical boreof slightly larger diameter than the diameter of the Kelly rod toprovide a clearance space therebetween for free sliding movement of theKelly rod through the bushing, said bushing having grooves ofsubstantially semicii'cular cross-section registering with the groovesin the Kelly rod and cooperating therewith to provide recesses ofcircular cross-section, cylindrical keys closely iitting within saidrecesses and having driven contact with the bushing substantially equalin area to driving contact with the Kelly rod, and sealing means at therespective ends of the bushing to retain said cylindrical keys.

4. In a drill rotating mechanism, a Kelly rod of circular cross-sectionand having longitudinal grooves of substantially semicircularcrosssection, a driving bushing having a cylindrical bore of slightlylarger diameter than the diameter of the Kelly rod to provide aclearance space therebetween for free sliding movement of the Kelly rodthrough the bushing, said bushing having grooves of substantiallysemioircular cross-section registering with the grooves in the Kelly rodand cooperating therewith to provide recesses of circular cross-section,cylindrical keys closely fitting within said recesses and having drivencontact with the bushing substantially equal in area to driving contactwith the Kelly rod, said driving and driven contact areas being locatedon diametrically opposite sides of said keys, means at the ends of thebushing engagingly retaining said cylindrical keys to preventlongitudinal movement of the keys in the bushing, sealing means at therespective ends of the bushing to retain said cylindrical keys, and

" assaooa means' connected with the Bushingmfof meeting a lubricantbetween said sealing means to 1111 4 the clearance space and providelubricantfor the cylindrical keys. r I

5, In a drill rotating mechanism, a Kellyrod of circular cross-,sectionand having longitudl` nal grooves of substantially semicylindricalcrosssection, a drive `bushing yfor theKelly rod having a bore passingthe Kelly rod therethrough and provided with grooves registering withthe Kelly rod grooves and of substantially semicylindcal cross-section,driving keys in said registering grooves of substantially cylindricalcross-section, and packing means at the respective ends of said bore toseal the bushing with the Kelly rod including means for retaining saidkeys from longitudinal movement in the grooves of the drive bushing.

6. In a drill rotating mechanism. a Kelly rod i of circularcross-section and having longitudinal grooves of substantiallysemicylindrical crosssection, a drive bushing for the Kelly rod having abore passing the Kelly rod therethrough and provided with groovesregistering with the Kelly rod grooves and of substantiallysemicylindrical cross-section, driving keys in said registering groovesof substantially cylindrical cross-section, packing means at therespective ends of said bore to seal the bushing with the Kelly rodincluding means for retaining said keys from longitudinal movement inthe grooves of the drive bushing, and means connected with the drivebushing for injecting a lubricant between said packing means forlubricating the keys in said grooves.

7. In a drill rotating mechanism, a Kelly rod having longitudinalgrooves, a drive bushing having a bore passing the Kelly rodtherethrough and provided with grooves registering with the Kelly rodgrooves, driving keys in said grooves, and packing means at therespective ends of said bore to seal the bushing with the Kelly rodincluding means for retaining said keys from longitudinal movement inthe grooves of the drive bushing.

8. In a drill rotating mechanism, a Kelly rod having longitudinalgrooves, a drive bushing having a bore passing the Kelly rodtherethrough and provided with grooves registering with the Kelly rodgrooves, driving keys in said grooves, packing means atthe respectiveends of said bore to seal the bushing with the Kelly rod including meansfor retaining said keys from longitudinal movement in the grooves of thedrive bushing, and means for injecting a pressure medium into the boreof the drive bushing.

9. In a drill rotating mechanism, a Kelly rod having longitudinalgrooves, a drive bushing having a bore passing the Kelly rodtherethrough and provided with grooves registering with the Kelly rodgrooves, driving keys in said grooves, said bushing having counterboresat the upper and lower ends thereof, and packing means in saidcounterbores to seal the bushing with the Kelly rod including means for'retaining said keys from longitudinal movement in the grooves of thedrive bushing.

10. In a drill rotating mechanism, a Kelly rod having longitudinalgrooves, a drive bushing having a bore passing the Kelly rodtherethrough and provided with grooves registering with the Kelly rodgrooves, driving keys in said grooves, said bushing having counterboresat the upper and lower ends thereof, washers in the bottoms of saidbores and having tongues extending into said Kelly rod grooves, packingsupported by said washers and having flexible tongues supported on saidtongues of the washers, and glands for retaining said packing.

11. In a drill rotating mechanism, a Kelly rod having longitudinalgrooves, a drive bushing having a bore passing the Kelly rodtherethrough and provided with grooves registering with the Kelly rodgrooves, driving keys in said grooves, said bushing having counterboresat the upper and lower ends thereof, washers in the bottoms of saidbores and having tongues extending into said Kelly rod grooves, packingsupportedby said washers and having flexible tongues supported on saidtongues oir the washers, and glands for retaining said t packing, saidglands having tongues extending into the Kelly rod grooves to cooperatewith the washer tongues in supporting the packing in sealing contactwith said grooves. 12.` In a drill rotating mechanism, a Kelly rodhaving longitudinal grooves, a drive bushing having a bore passing theKellyrod therethrough and provided with grooves registering with theKelly rod grooves, driving keys in said grooves, said bushinghavingcounterbores at the upper and lower ends thereof, washers in the bottomsof said bqres and having tongues extending into said Kelly rod grooves,packing supported by said washers and having flexible tongues supportedon said tongues of the washers, glands for retaining said packing, andmeans for retaining said washers in the bottoms of said bores.

WALTER T. CALDWELL.

